Correlation between serum adenosine deaminase activity and efficacy of anti-programmed cell death-1 antibody

Generation of a Retargeted Oncolytic Herpes Virus Encoding Adenosine Deaminase for Tumor Adenosine Clearance

Background: Oncolytic viruses are immunotherapeutic agents that can be engineered to encode payloads of interest within the tumor microenvironment to enhance therapeutic efficacy. Their therapeutic potential could be limited by many avenues for immune evasion exerted by the tumor. One such is mediated by adenosine, which induces pleiotropic immunosuppression by inhibiting antitumor immune populations as well as activating tolerogenic stimuli. Adenosine is produced starting from the highly immunostimulatory ATP, which is progressively hydrolyzed to ADP and adenosine by CD39 and CD73. Cancer cells express high levels of CD39 and CD73 ectoenzymes, thus converting immunostimulatory purinergic signal of ATP into an immunosuppressive signal. For this reason, CD39, CD73 and adenosine receptors are currently investigated in clinical trials as targets for metabolic cancer immunotherapy. This is of particular relevance in the context of oncovirotherapy, as immunogenic cell death induced by oncolytic viruses causes the secretion of a high amount of ATP which is available to be quickly converted into adenosine. Methods: Here, we took advantage of adenosine deaminase enzyme that naturally converts adenosine into the corresponding inosine derivative, devoid of immunoregulatory function. We encoded ADA into an oncolytic targeted herpes virus redirected to human HER2. An engineered ADA with an ectopic signal peptide was also generated to improve enzyme secretion (ADA-SP). Results: Insertion of the expression cassette was not detrimental for viral yield and cancer cell cytotoxicity. The THV_ADA and THV_ADA-SP successfully mediated the secretion of functional ADA enzyme. In in vitro model of human monocytes THP1, this ability of THV_ADA and THV_ADA-SP resulted in the retrieval of eADO-exposed monocytes replication rate, suggesting the proficiency of the viruses in rescuing the immune function. Conclusions: Encoding ADA into oncolytic viruses revealed promising properties for preclinical exploitation.

The Applicability of ADA, AFU, and LAC in the Early Diagnosis and Disease Risk Assessment of Hepatitis B-Associated Liver Cirrhosis and Hepatocellular Carcinoma

Objective: This study aimed to evaluate the applicability of adenosine deaminase (ADA), α-l-fucosidase (AFU), lactic acid (LAC), and their combined detection in the early diagnosis of chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). Methods: A retrospective analysis of hepatitis B-positive liver disease patients admitted between 2015 and 2020 was conducted. The receiver operating characteristic (ROC) curve was used to determine the diagnostic value of each indicator in LC and HCC, and binary logistic regression analysis was performed to determine the factors and risks related to the occurrence of the two conditions. Results: The levels of ADA, AFU, and LAC were significantly increased in patients with CHB, LC, and HCC (p < 0.05). The ROC curve showed that the sensitivity and specificity of ADA, AFU, LAC, and their combined detection in the CHB and LC groups as well as in the LC and HCC groups reflected different degrees of clinical value. In the CHB and LC groups, the adjusted odds ratio (OR) values of ADA, AFU, and LAC among patients in the high-level group were 3.218, 1.859, and 11.474, respectively, when the median was considered the cutoff point. When quartiles were considered the cutoff point, the OR risk values of the adjusted levels of ADA, AFU, and LAC were higher than those of the lowest-level group (Q1) (p < 0.05). In the LC and HCC groups, the adjusted OR values of ADA, AFU, and LAC among patients in the high-level group were 0.967, 2.365, and 38.368, respectively. When quartiles were considered the cutoff point, the OR risk values of AFU and LAC levels were higher than those of the lowest-level group (Q1) (p < 0.05). Conclusion: ADA, AFU, and LAC demonstrated good value in the early diagnosis of LC and HCC. The combined detection of ADA+AFU+LAC is more effective than single detection for the early diagnosis of the two conditions. ADA, AFU, and LAC can serve as risk predictors of LC, while AFU and LAC can be considered early risk predictors of HCC.

The effect of 5-substituent in cytosine to the photochemical C to U transition in DNA strand

Nucleobase editing is a powerful tool in genetic disease therapy. We have reported the photochemical transition of cytosine to uracil using an ultrafast DNA photo-cross-linking. In this study, we used cytosine derivatives such as methylcytosine, hydroxymethylcytosine, and trifluoromethylcytosine to evaluate the effect of 5-position substitution of cytosine on deamination. The conversion of cytosine to uracil was the fastest, and the conversion of trifluoromethylcytosine to trifluoromethyluracil was the slowest. The order was correlated with the hydrophilicity of the double strand containing these cytosine derivatives.

Photochemical RNA Editing of C to U by Using Ultrafast Reversible RNA Photo-crosslinking in DNA/RNA Duplexes

RNA editing, which is used to edit nucleobases in RNA strands; is more feasible for use in medical applications than DNA editing. We previously reported the photochemical conversion of cytosine to uracil, which required photo-crosslinking, deamination, and photo-splitting. Here, we evaluated the influence of the bases surrounding the target cytosine on the conversion of cytosine to uracil in the RNA strand. The photo-crosslinker 3-carboxyvinylcarbazole(^OHV K), which is more hydrophilic than 3-cyanovinylcarbazole(^CNV K), 3-carboxyamidevinylcarbazole(^NH2V K), and 3-methoxy carbonylvinylcarbazole(^OMeV K), induced faster deamination of cytosine. Furthermore, inosine, which forms two hydrogen bonds with cytosine, was the most efficiently paired base for accelerating photochemical RNA editing. Upon evaluation of the conversion from cytosine to uracil in RNA, the use of oligodeoxynucleotides containing ^OHV K and inosine and the polarity of the bases surrounding the target cytosine were found to be crucial.

Nivolumab treatment beyond progressive disease in advanced non-small cell lung cancer

PURPOSE

This study evaluated the efficacy and safety of nivolumab treatment beyond progressive disease (PD) in non-small cell lung cancer (NSCLC).

PATIENTS/METHODS

Medical records of consecutive patients with advanced NSCLC who received nivolumab between December 2015 and December 2018 were reviewed. Clinical outcomes of three groups of eligible patients who received nivolumab as a second-line treatment after PD were compared based on Response Evaluation Criteria in Solid Tumors v1.1. We conducted subgroup analyses in patients with and without new lesions at first PD.

RESULTS

Twenty-eight patients continued nivolumab treatment beyond PD (TBP). Post PD, 46 patients switched to other anti-cancer treatment (OAT), and 21 received no further anti-cancer treatment (NAT). There were no significant differences in overall survival (OS) or survival post progression (SPP) between TBP and OAT groups (OS: 15.6 vs. 13.4 months, P = .40, SPP: 12.2 vs. 9.3 months, P = .42). Subgroup analyses indicated that among patients without new lesions at first PD, SPP was longer in the TBP than in the OAT groups (12.6 vs. 9.3 months, P = .22, HR: 0.64; 95% CI 0.31‒1.31). The frequency of immune-related adverse events leading to discontinuation during nivolumab beyond PD was equivalent to that for pre-PD (10.7 vs. 12.6%).

CONCLUSIONS

No significant benefits were associated with continuation of nivolumab for advanced NSCLC patients. Continuation of nivolumab beyond PD could be a more useful option in patients without new lesions at first PD. Treatment-related toxicities require attention during nivolumab treatment not only before PD but also beyond PD.